Dozens of researchers and students are chasing thunderstorms across the country this summer to collect data for what experts say is the largest hail study conducted in the United States in more than 40 years.

For six weeks this summer, scientists from 15 U.S. research institutions and three international research institutions are traversing the country, from Texas to Montana to Kansas to North Dakota.

Included in the armada are teams from the University of Colorado Boulder and the National Center for Atmospheric Research, who are collecting hail data to analyze it and gain a better understanding of hailstorms and how to improve hail forecasting models.

The study is called the In-situ Collaborative Experiment for the Collection of Hail In the Plains, or ICECHIP, and is funded entirely by the National Science Foundation. CU Boulder professor Brian Argrow said more than 70 scientists and students are involved and that people rotate in and out due to the length and intensity of the work. The CU Boulder team has six or seven people working at a time out of a rotation of 10 or 11 people, he said.

The researchers track the storms across state lines and get into position so that when the storm approaches, they lay out array of instruments along the road to collect data.

“It’s extremely exhausting, the field work being done,” principal investigator and senior NCAR scientist Andy Heymsfield said. “People don’t get back to their hotels until 1 a.m. often, and are driving at night on narrow roads and long distances in heavy rain or hail. So I would emphasize how proud I am of the people in the field who are exhausted but doing a great job of collecting data.”Heymsfield was also involved in the last major U.S. hail study, the National Hail Research Experiment, which was conducted in the 1970s. He said the NHRE collected valuable data regarding the properties of the hailstorms and the sizes of hailstones, adding that today’s hail study benefits from “tremendous technological advancements.”

“Now we have much better radar data (and) much better observations of hail at the ground,” Heymsfield said. “What they’re doing now is a lot of 3D scans of the hailstones so you can get their shape. And there are many other aspects that are very advanced.”

Heymsfield said he’s often wondered why it took nearly 50 years to conduct another major hail study in the United States. In part, he thinks it may be because hurricanes and tornadoes are perceived as more damaging, and that hailstorms are not quite as dramatic or eye-catching.

But, hail storms cause billions of damage annually, and the New York Times reported that insurers are experiencing rising hail damage claims. In 2017, a single hailstorm in the Denver area caused $2.3 billion in damage.

“There’s far more damage from hail every year than tornadoes and other windstorms,” Argrow said.

Heymsfield said he’s “thrilled” that this hail study is being done.

“I think this will advance the field,” Heymsfield said. “One of the things I’m very interested in personally is to provide early warning of hail and impending damaging hail … so people, for example, can put their cars in the garage …and avoid potentially injury.”

The CU Boulder team focuses on piloting RAAVEN, the university’s storm-chasing drone that inspired filmmakers to create a version of it for the “Twisters” movie, released last summer. While RAAVEN was originally designed for tornado research, it’s now being used for this hail study. The RAAVEN drone, which looks like a small airplane, carries a downward-facing camera documenting the ice it flies over. The researchers follow the storm on the road with an airplane above them.

“Our job is to fly behind the storm as close as we can to capture the hail swath,” Argrow said.

RAAVEN doesn’t fly directly into the storm. Instead, it stays behind the storm, collecting information on the area below that’s covered in ice from the passing storm. Researchers can then measure the width of the hail swaths and capture data on the size of the storm’s path.

CU Boulder professor Katja Friedrich wants to study how hail grows and forms. She’s interested in why storms have small versus big hail, and what the indicators are for a hailstorms that drop a foot of hail.

“I’m trying to understand how these hail-accumulating thunderstorms form and what is so different from regular thunderstorms,” Friedrich said.

Another component of the study is materials testing, where an entire team is testing different materials for hail resistance to help build stronger roofs and sidings.

Friedrich said when hail warnings go out, it’s for the entire Front Range. But, while one city sees a lot of hail, another might see none. If scientists can gain a better understanding of hail through this study, it could increase forecast accuracy and precision.

“These types of studies will enable weather radar to be more effective in giving warnings in terms of calibrating what the radar is reporting versus what is actually happening on the ground,” Argrow said.

He added that Colorado is one of the leading states in the country for annual hail damage, making this work even more critical at home.

“We do it in part because of the opportunity to participate in activities that directly impact public safety and in terms of both property and lives,” Argrow said. “And so it’s an opportunity for us to take our engineering and apply it in an area of national need. And that’s really what I think makes this work, for me anyway, is what makes it so fulfilling. This is not about the latest theory, it’s about what’s actually happening and how we can use engineering to address the needs of society.”